Process and apparatus for increasing the flow of subterranean fluids into wells



J. B. M ELHENY Oct. 16, 1962 3,058,523 PROCESS AND APPARATUS FORINCREASING THE FLOW Ll/ENY INVENTOR. MCE

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2 Sheets-Sheet 1 OF SUBTERRANEAN FLUIDS INTO WELLS Filed April 15, 1959J. B. M ELHENY PROCESS AND APPARATUS FOR INCREASING TH Oct. 16, 19623,058,523 E FLOW OF SUBTERRANEAN FLUIDS INTO WELLS 2 Sheets-Sheet 2Filed April 15, 1959 H LK? INVENTOR.

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3,058,523 PROCESS AND APPARATUS FOR WCREASING $LOW OF SUBTERRANEANFLUIDS INTO John B. McElheny, 11552 Las Palmas Drive, Fullerton, Calif.Filed Apr. 13, 1959, Ser. No. 805,865 1 Claim. (Cl. 166-554) Thisinvention relates to the productivity of wells, and particularly to oilwells.

Wells of this character may be of very considerable depth, and cased bywell casing except at the bottom. Oil or other fluid material may flowfrom the earth formation into the well bottom through fissures, cracksand crevices in the layers exposed in the bottom.

In order to increase the flow of oil or gas, it is necessary to enlargethese fissures or crevices, or to create new fractures or fissures. Inthe past, this has been done by the creation of high fluid pressuresusually produced by detonating explosives by the aid of a firing circuitcontrolled from above the ground. For example, solid or liquidexplosives, deposited in the bottom of the well, have been detonated toproduce explosive blasts.

It is one of the objects of this invention to make it possible to createor enlarge such fissures or crevices or cracks in a simple and safemanner.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalembodiments of the invention. For this purpose, there are shown a fewforms in the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is an elevation of apparatus utilized to practice theinvention, shown as disposed within a well, the depth of the well beingshortened in order to reduce the size of the figure;

FIG. 2 is a view, mainly in longitudinal section, of a portion of theapparatus illustrated in FIG. 1;

FIG. 3 is a view similar to FIG. 2, but illustrating the ignitingposition of the apparatus; and

FIG. 4 is a view similar to FIG. 1, but showing the use of the apparatusin a casing, instead of in an exposed formation. f

In FIG. 1 there is illustrated a well 1 having tubular casing 2extending downwardly to an uncased lower portion or end 3. Into this end3 leads :a number of fine fissures, crevices or cracks indicated byreference character 4. Through these fissures, crevices or cracks flowspetroleum or gas, or both, into the well bottom 3.

In order to increase the flow into the end 3, a slow burning propellantis ignited in the well. Such propellants, in liquid or solid form, arenow well-known, and. are often used for propelling rockets. Thepropellant in this instance is indicated as a package 5 (see also FIGS.2 and 3). This package 5 is intended to be ignited by the aid ofapparatus described in detail in a prior application filed in the nameof the present applicant on April 7, 1958, under Serial No. 726,709, andentitled Oil Well Casing Perforator.

The slow burning propellant material 6 produces constantly increasingpressures in the space in which it is confined. It may be covered by athin plastic shell 7.

To increase the ultimate pressure, a succession of such packages may beignited at spaced intervals.

The package 5 includes a booster igniter cord 8 which 3,fl58,523Patented Oct. 16, 1952 extends into the interior of the solid propellant6. If solid propellant is utilized, it may conveniently be carried onthe lower threaded end 9 of a carrier 10. The booster 8 may be placed incommunication with an explosive charge 11 normally separated by arupturable wall 12 from a dry charge 13. Both the charge 11 and the drycharge 13 can be carried in appropriate recesses in the carrier 10.

The upper end 14 of the carrier 10 is threadedly engaged by the lowersleeve-like end 15 of a firing mechanism 30. The firing mechanismincludes a firing pin 16 adapted to fire a cartridge 37 at the upper endof the recess accommodating the dry charge 13, and thereby to causeignition of charges 13 and 11, and rupturing of wall 12. By the aid ofappropriate sealing rings 31, 32, the space accommodating charge 13 issealed against entry of well liquid until firing is accomplished. Thenthe explosive force of the dry charge is sufficient to detonate thecharge 11, even if it be wet, after wall 12 is punctured.

As explained in said prior application Serial No. 726,- 709, the firingpin 16 is held against firing by the aid of a tubular guide 17cooperating with one or more lever arms 18 which hold the enlarged head19 of the pin 16 in inactive position.

The tubular guide 17 extends upwardly to the surface of the well. A pump20 serves to provide fluid pressure to urge the firing device downwardlyas by operating on a flexible-type piston 21 appropriately joined to thefiring device body 22. The fluid from the well bottom 3 is urged by thispumping action into the formation.

Just as soon as the firing mechanism passes downwardly beyond theguiding tube 17, the lever arms 18 are freed of restraint and releasethe head 19 of the firing pin 16. This condition is illustrated in 'FIG.3. In this position, the firing pin is projected by hydraulic pressureexisting in the well 1 through an appropriate guiding aperture in acollar 23, to fire the cartridge 37. At the same time, the wall 12 isruptured and the charge 11 is ignited to ignite the booster 8 andthereby the propellant 6.

In order to maintain the space adjacent the end 3 in sealed position, apacker 24 is provided surrounding the tubular member 17 and inengagement with the well casing 2. Furthermore, when the firingmechanism moves out of the bottom of the tubular guide 17, a check valveclosure 25 is urged by spring pressure to closed position, as indicatedin FIG. 1. This check valve may be of any conventional form urged toclosed position by a light spring, such as shown in US. Patent No.2,507,262 to McGivern, that would not appreciably retard the passage ofthe igniting device and the propellant passage through the bottom of thetube 17.

The gradually increasing pressure due to the igniting of the slowburning propellant fuel package 5 serves to enlarge or to increase thenumber of the passageways through which fluid or liquid can flow intothe bottom of the well. This is accomplished without violent explosiveforces. The process may be repeated several times in order to accumulateand constantly increase the fluid pressures existing in the bottom ofthe well.

FIG. 1 illustrates the use of the invention in an open hole. However, asshown in FIG. 4, the invention may be practiced in connection with aperforated casing section 26. This section is in communication by theaid of the perforations 27 with a producing layer 28. The samebeneficial effects are obtained as in the form of FIG. 1.

The inventor claims:

In a system for increasing flow of fluids into a well extending througha formation having a producing portion: a tubular guide extending fromthe top of the well to a place adjacent the producing portion; a packageof propellant material guided in said guide, and adapted to emerge fromthe guide into said portion; means carried by the package for ignitingthe propellant when it leaves the guide, including a latch released bymovement of the package beyond the guide; a sealing device between theguide and the Well to seal off the producing portion; a closure for thebottom of the guide, movable exteriorly of the guide; and means forurging the closure to closed position, upon exit of the package from theguide, where-' by fluid pressures may he built up in the producingportion for forming or enlarging crevices, cracks and fissures in theformation around said portion.

References Cited in the file of this patent UNITED STATES PATENTS2,676,662 Ritzmann Apr. 27, 1954 2,705,920 Kanady Apr. 12, 19552,766,828 Rachford Oct. 16, 1956 2,859,697 Long Nov. 11, 1958 2,876,843Huber Mar. 10, 1959

